I have just installed a 64-bit Ubuntu guest on a quad-core 64-bit Windows XP host in VirtualBox, and I am trying to get the guest to use multiple cores.
However, when I go to Settings -> System -> Processor, the Processor(s) slider bar is greyed out, and when I hover over it the following message appears:
You need hardware virtualization support on your host system to use more tha one virtual CPU.
How do I go about geting this hardware virtualization support?
EDIT: I should mention, my processor is a Core i5 750.